Finish applicator



iom. 19, 1943. R. M. HOFFMAN am. .2,331,980

FINISH APPLICATOR Fiied July so, 1940 ATTORNEY lBY Patented oct. `19, 1943 rnvrsn mucs'ron 1 Robert M. Hoffman and Ira Y. Hitt, Waynesboro Va.. assisnors to E. I'. 'du Pont de Nemours Company, Wilmington, Del., a corporation of Delaware A Application July 30, 1940, Serial N0. 348,408

roam (c1. :i1-5o) 'I'his invention relates to the manufacture of filaments; yarns; threads. and the like, and more particularly to a device for applying liquid to travelling articial filamentayarns, threads and the like, and even more particularly to a double roll device for applying` finish composition to ments, yarns or threads. A further object is to' travelling iilaments, threads and yarns of cellulose actate.

In the manufacture of laments, threads or yarns of cellulose acetate it is the practice to apply to the filament, thread or yarn, prior to its being wound. into package form, a finishing composition which functions principally to reduce or eliminate the effect of electrostatic charges, to lubricate and protectthe filaments from the rubbingand abrasive action of guide surfaces, and to hold together the substantially parallel filaments which form an untwisted yarn whereby aqueous finish compositions to artificial fila- 1 provide a device which will operate to supply a constant and even lm of proper thickness 'of non-aqueousI finish composition for application to av travelling filament, yarn or thread of cellulose acetate or like artificial material. A still further object is to provide a double roll applicator that willv permit ofthe application of nonaqueos finish compositions in proper and uniform amount, to travelling artificial filaments.

v yarns or threads without appreciably affecting the yarn may be wound into a satisfactory Y package.

Through the application of aqueous finish compositions it has been possible to get, with comparative ease, a reasonably high total liquid volume on yarn, without, however, too high a concentration of non-volatile material, such as vegetable oil or other lubricating and/0r softening agent. A high percentage of finish composition is desirable in that it tends to bind and stick the group of laments together, andassists the lay of the yarn on the wind-up package to the end that there is obtained a good package. Aqueous finish compositions therefore have been widely used in the past. Experience, however, has shown that all aqueous finishes have a tendency to occlude in newly dry-spun cellulose acetate yarn and this occlusion has been definitely established to result in non-uniform dyeing of the yarn which defect manifests itself in the appearance of unsightly streaks and unevenly dyed areas in the fabrics produced from the yarn.

It has been found that when non-aqueous finish compositions are substituted for aqueous compositions the occlusion of finish is minimized and the dyeing qualities of the yarn are improved to a marked extent. Furthermore the composition must be applied with a greater degree of constancy and of uniformity if satisfactory results are to be-obtained. The conventional types of finish applicator do not give the uniformity and I constancy offeed required nor do they permit of the application of uniformly small amounts of composition in many instances, and hence cannot be used in applying non-aqueous finish compositions totravelling artificial filaments, yarns or threads.

An object of this invention therefore is'to provide an improved device for. applying liquids to travelling laments, yarns and threads. Another object is'to provide an applicator device which jisparticularly suited for the application of nonthe travel of the filament, yarn or thread to the end that a satisfactory cake orpackage of filament, yarn or thread may be formed. These and other objects will more clearly appear herein-- after.

'I'hese objects are accomplished by the following described invention.

From a study of the mechanics of finish aprplication we have determined that a double roll arrangement is best adapted for applying nonaqueous finish compositions and that such an arrangement must satisfy the following requirements; A

l. Use of a very smalldiameter yarn contacting roll, which permits the yarn to be bent there- 'around at a noticeable but small angle which can be accurately controlled without; however, inducing undesirably high tensions in the yarn.

2. Minimize surface tension and prevent disturbance of the finish film on the yarn applicator roll so that even though the yarn makes a slight bend around the small diameter yarn contacting roll it does not appreciably curve or hug the surface, i. e. the actual length of contact is very short.

3.7Maintain the thickness of nish film on Athe roll uniformly constant at all times.

Briey. this invention consists of two rolls, one rotatably mounted to contact the thread, .yarn or filament and of such small diameter that the line of contact may be substantially a point. and a second rotatably mounted roll of lgreater diameterhaving its lower portion immersed in `a pool of finish composition and spaced from the `rst roll a denite predetermined distance greater than the thickness ofthe iilm of nish composition picked up by the second roll but which is not greater than the distance that can be bridgedbyfthe nish composition. Both rolls are posifulfills the requirementsoutlined above.

A clear understanding of the structure and operation of our invention may be had by, reference to the 'accompanying drawing wherein:

Figure 1 is an end-sectional view of' a preferred form of our device showing its relative position to the cone tip of a drying spinning cell and the yarnl wind-up package;

' predetermined amount Figure 2 is a plan view of the device of Figure 1; and

Figures 3 and 4 are plan views of modifications of our improved applicator device.

In Figure 1, l designates a bundle of filaments iss'uing from the spinning cell cone tip 2, guided by means of members 3 'and i0, passing under a,

draw roller I and onto a wind-up device to form the yarn package 5. On a suitable support 3| is located a trough 3l)` containing an aqueous or other suitable yarn finish 32 into which gips a cylindrical roller 20 mounted -on shaft 2l. Adjacent this roller is a much smaller uniform diameter roller 23, spaced from roller 20 a small predetermined amount :c of the order of 0.02". Rollers 420 and 23 are positively driven, for instance, by means of gears 42 and I3, meshing together, and 42a (shown in Figure 2) meshing with gear 4I on a drive shaft 40, driven in any suitable manner. Preferably, the surface speed of the two rolls 20 and 23 are maintained the same, although this is not essential. Also, it is preferred that shaft Il turn in a clockwise direction so that the thread wiper roll 23 is turned in the same direction as the yarn travels. Guide member I Il is supported in the bracket Il, pivotable about rod i2 in order t'o adjust and maintain the angle of the thread with the wiper roll 23 uniform and constant from position to position. The 'arcuate contact of the thread with the roll should be small, for example about to degrees.

In Figure 3 is shown a modied form of this invention wherein the roll dipping in the finish is of reduced diameter over. a portion of its length so that portion adjacent the middle part of the thread contacting roll 33 is spaced a certain in order to control the finish film thickness with which the yarn will contact in passing over the central portion of roll I3. In this case, since the surfaces controlling the thickness of finish film are spaced at the desired distance, it is unnecessary that roll tive thereto. The yarn applying roll should be kept as small as possible coincident with good' 5 inches'or more in diameter, so as better to accommodate the smaller yarn applying roll relaengineering practiceand design for uniformity throughout the many positions comprising the spinning machine, for example, less than 1" and I preferably no more than 3/4 in diameter.

53 be free of contact with roll 5I, but by making contactwith the shoulders 55 of the roll 50 as indicated, a constant spacing of the effective surfaces can easily be maintained.

In Figure 4 the yarn contacting roll 63 is of reduced diameter in the central portion so that there is a definite predetermined space between this middle. undercut portion and the roll dipping into the finish. The shoulders 8l of the yarn applying roll 63 press againstthe larger roll and thereby'maintain the space between Ythe two effective surfaces constant. 'I'he thread contacting surface of roll 63 may be roughened. for instance by etching, sandblasting, knurling, or serrating with fine longitudinally extending teeth or projections ranging from to 120, or more. per inch.

Since the distance :c between Vthe rolls is greater than the thickness of the film of finish composition picked up by the roll dipping into the composition, the device must be primed in order to initially establish a bridge of composition between the two rolls. ThisV is preferably accomplished by pouring sufficient composition I onto the rotating yarn applying roll to wet the ping into the finish relatively large, say 2 to 4 or The two rolls are preferably made of hard. non-corrodible material, such as stainless steel, nickel, nickel alloys, etc.

The peripheral speed of the effective surfaces of the two rolls may vary quite widely, say from 1 to 100 feet per minute, although with certain liquids a lower or higher speed may be more suitable. For example, more liquid is carried by a rough-surfaced roll than by a smooth-surfaced roll, and the eifectiveroll speeds should be adjusted accordingly. Also, with non-aqueous finishes a much lower roll speed is desired, since the volume of liquid to be applied ismuch less than with aqueous finishes. The yarn denier and the amount of finish desired on the ilnal product also should be considered in determining the roll speeds.

It is preferred that both rolls be positively driven so as to insure a constant speed of rotation, whether the speed be high or low. It has beendetermined, for instance. that at peripheral speeds above 36 feet per minute frictionally driven rolls tend to slip in a haphazard` fashion, and as a consequence the application of finish composition is not uniform. Positive drive of both rolls eliminates this difliculty.

The distance :c between the two rolls will be adjusted according to the character cf the liquid to be applied to the yarn. ,Such an adjustment may be fixed and permanent or-obvious means may be employed to adjustably mount one roll with respect to the other so that the distance between therolls may 'be adjusted at will. For most yarn finishes, the optimum distance will be found between 0.01 inch and 0.03 inch, although with certain other liquids a spacing as much as 0.035 inch, or even 0.04 inch may be found advantageous. This distance, which depends largely upon the surface tension and viscosity of the liquid, must not be so great that the liquid fails to bridge thev gap between the wette'd rolls.

A practical application of our device is illustrated by the following examples.

In applying 3.5% finish to l5 denier, 24 filament cellulose acetate yarn spun from an acetone solution by the evaporative method and being wound up as untwisted yarn at 500 yardsper minute, the following conditions were found very satisfactory. The two rolls (Figure 1) were Percent Sulfonated olive oil..l 5

` Rened mineral oil 10 Water 85 may be different. The roll diameters In applying 3.0% of an oil finish to 55 denier 18 filament cellulose acetate untwisted yarn being wound up at 500 yards vper minute, the surface speed of the rolls were maintained the same at 4.5 feet per minute, the smaller roll 6%, in diameter) rotating in the same direction as the finish composition was:

. Parts Palm kernel oil 60 Rened mineral oil 40 Both yarns were found to be of good quality and uniform in their properties, especially dyeing, and after twisting and coning they could be used to good advantage as the warp or lling, or as both, in woven goods to produce high quality fabrics free from streaks and other defects.

Although this invention has been described with reference to the finishing of cellulose acetate yarn non-aqueous finish compositions at the spinning machine, it is equally applicable to the finishing of any textile iilamentary material in the course of yarn travel'on any type winding machine, such as a throwing, winding, spooling, or creeling machine, and with aqueous as well as non-aqueous finish compositions. Also, the invention is not limited to the finishing of untwisted filament bundles, but is applicable to the liquid application to twisted yarns or threads. Instead of applying a lubricating or softening composition, this device is also suited to the application of any liquid to the yarn, such as a tint, dye, dope, size, or the like.

Our improved device enables desirable dressing compositions to be applied to the yarn which heretofore could not satisfactorily be controlled due to the limitations in prior art finish applicators. It is thus possible. to "use non-aqueous finishes and obtain excellent package formation with the attendant high quality yarn, i. e. freedom from broken or frayed laments, and at the same time get acceptable uniformity of dyeing which was not possible with the finish applicators used heretofore.

The invention is especially advantageous in the application of non-aqueous as well as aqueous compositions because a wide range of roll speeds may be used, the rate of finish application can be varied over wide limits and this arrangement s exceptionally useful in the uniform application of finish to yarns being wound at very high speeds, such as 500 or more yards per minute. Inasmuch as a very small contact is maintained between the yarn and the yarn contacting roller due to its small diameter, uniformity of application far exceeds that of any other known method of applying finish to a yarn traveling at high speeds.

It is understood that the invention is not limited to the exact arrangements, dimensions, and applications described above, but comprehends rather al1 modications and equivalents falling within the spirit and terms of the following claims.

We claim:

1. In a device for applying liquid compositions to nlaments, yarns and threads, a first rotatably mounted roll oi' relatively large diameter positioned to pick up a lm of liquid composition from a body of thev same, a second rotatably mounted roll of relatively small diameter positioned to pick up a film of liquid composition from said first roll and to contact the yarn whereby to transmit the liquid composition to the yarn, spacing means operative to maintain said second roll positively spaced from said first roll a definite predetermined distance greater than the thickness of the nlm picked up by said rst roll and not greater than the distance that can be bridged by the liquid composition, and means to guide said filaments, yarns and threads into contact with said second roll.

2. A device according to claim 1 wherein the yarn contacts the second roll on a line which isa small increment of the circumference of said second roll'.

3. A device according to claim 1 wherein both rolls are positively driven.

4. A device according to claim 1 wherein both rolls are positively driven and the spacing means comprise a raised portion at each end of said first roll, said raised portion forming a shoulder having a thickness equal to the predetermined distance between the rolls, which shoulder contacts the second roll whereby the second roll is positively spaced the the rst roll. l-

5. A device according to' claim 1 wherein both rolls are positively driven and the spacing means comprise a raised portion at each end of said second roll, said raised portion forming a. shoulder having a thickness equal to the predetermined distance between the rolls, which shoulder contacts the first roll whereby the second roll 4is positively spaced the predetermined distance from the first roll.

- 6. A device for applying liquid compositions to travelling filaments, yarns, and threads which comprises a trough for liquid composition, a rotatably mounted, positively driven roll of relatively large diameter, said roll being partly submerged in the liquid composition along a line parallel to its axis of rotation, whereby said roll picks up a film o1' the liquid composition, a second positively driven roll of relatively small diameter, said second roll being positioned to pick up liquid composition from the rst roll, guide means adjustably mounted to guide the travelling yarn in contact with said second roll unl a line which is a small increment of the circumference of the roll, spacing means operative to maintain said second roll positively spaced from the larger roll a definite predetermined predetermined distance from distance greater than the thickness of the film of positively spaced from said rst vroll from about 

